Twin Wire Fire Alarms
Twin wire fire alarm systems are similar to a conventional system as they have detection zones. The main advantage of twin-wire systems is you can put sounders on the detection circuit which means you can save on the cost of having to wire additional sounder circuits.
Each call point or smoke alarm is connected to the main fire alarm control panel by its own wire. When a detector is triggered, the fire alarm control panel will operate the sounders for a full evacuation. A twin wire system allows sounders to be installed on the circuit, meaning you don’t need to wire in additional sounder circuits.
What are the advantages of a twin wire fire alarm system?
- Supports remote input/output interface units. So if, for example, lift control shutdown is required but the lift is sited a long way from the fire alarm control panel, the remote input/output can operate this with minimal wiring.
- Save the cost of wiring additional sounder units
- Reduce false alarms – the alarm is sounded only in the zone where the fire is detected. If a fire continues to be detected the alarm will sound in the whole building. If a fire isn’t detected then the system is automatically reset.
What are the disadvantages of a twin wire system?
- Although cheaper to buy it’s more expensive to install
- The exact location of a fire can’t be given with a twin wire fire alarm system. However, by wiring different floors or areas as zones, then an indication of which zone the fire is in can be given.
- If a wire becomes severed, the device is disconnected and may not signal the presence of a fire.